<p>给定一个&nbsp;<code>8 x 8</code> 的棋盘，<strong>只有一个</strong> 白色的车，用字符 <code>'R'</code> 表示。棋盘上还可能存在白色的象&nbsp;<code>'B'</code>&nbsp;以及黑色的卒&nbsp;<code>'p'</code>。空方块用字符 <code>'.'</code>&nbsp;表示。</p>

<p>车可以按水平或竖直方向（上，下，左，右）移动任意个方格直到它遇到另一个棋子或棋盘的边界。如果它能够在一次移动中移动到棋子的方格，则能够 <strong>吃掉</strong> 棋子。</p>

<p>注意：车不能穿过其它棋子，比如象和卒。这意味着如果有其它棋子挡住了路径，车就不能够吃掉棋子。</p>

<p>返回白车 <strong>攻击</strong>&nbsp;范围内 <strong>兵的数量</strong>。</p>

<p>&nbsp;</p>

<p><strong>示例 1：</strong></p>

<p><img alt="" src="https://assets.leetcode-cn.com/aliyun-lc-upload/uploads/2019/02/23/1253_example_1_improved.PNG" style="height: 305px; width: 300px;" /></p>

<pre>
<strong>输入：</strong>[[".",".",".",".",".",".",".","."],[".",".",".","p",".",".",".","."],[".",".",".","R",".",".",".","p"],[".",".",".",".",".",".",".","."],[".",".",".",".",".",".",".","."],[".",".",".","p",".",".",".","."],[".",".",".",".",".",".",".","."],[".",".",".",".",".",".",".","."]]
<strong>输出：</strong>3
<strong>解释：
</strong>在本例中，车能够吃掉所有的卒。
</pre>

<p><strong>示例 2：</strong></p>

<p><img alt="" src="https://assets.leetcode-cn.com/aliyun-lc-upload/uploads/2019/02/23/1253_example_2_improved.PNG" style="height: 306px; width: 300px;" /></p>

<pre>
<strong>输入：</strong>[[".",".",".",".",".",".",".","."],[".","p","p","p","p","p",".","."],[".","p","p","B","p","p",".","."],[".","p","B","R","B","p",".","."],[".","p","p","B","p","p",".","."],[".","p","p","p","p","p",".","."],[".",".",".",".",".",".",".","."],[".",".",".",".",".",".",".","."]]
<strong>输出：</strong>0
<strong>解释：
</strong>象阻止了车吃掉任何卒。
</pre>

<p><strong>示例 3：</strong></p>

<p><img alt="" src="https://assets.leetcode-cn.com/aliyun-lc-upload/uploads/2019/02/23/1253_example_3_improved.PNG" style="height: 305px; width: 300px;" /></p>

<pre>
<strong>输入：</strong>[[".",".",".",".",".",".",".","."],[".",".",".","p",".",".",".","."],[".",".",".","p",".",".",".","."],["p","p",".","R",".","p","B","."],[".",".",".",".",".",".",".","."],[".",".",".","B",".",".",".","."],[".",".",".","p",".",".",".","."],[".",".",".",".",".",".",".","."]]
<strong>输出：</strong>3
<strong>解释： </strong>
车可以吃掉位置 b5，d6 和 f5 的卒。
</pre>

<p>&nbsp;</p>

<p><strong>提示：</strong></p>

<ol>
	<li><code>board.length == 8</code></li>
	<li><code>board[i].length == 8</code></li>
	<li><code>board[i][j]</code> 可以是&nbsp;<code>'R'</code>，<code>'.'</code>，<code>'B'</code>&nbsp;或&nbsp;<code>'p'</code></li>
	<li>只有一个格子上存在&nbsp;<code>board[i][j] == 'R'</code></li>
</ol>
